Filter having vertical filter elements

ABSTRACT

A filter has a vertically disposed housing, a support plate and vertical filter elements fixed at their upper ends to the support plate and supported thereby in the housing. A water outlet tube passes through the center of the support plate and exits at the base of the filter. The water outlet pipe is connected to the support plate in leak-tight manner and the portion of the filter located above the support plate is removable.

BACKGROUND OF THE INVENTION

The present invention relates to filters having vertical filterelements, for example cartridge filters or candle-shaped filters assupports for a preliminary layer, which are used for the treatment ofcondensed water, particularly but not exclusively in the nuclearindustry.

Known filters comprise a cylindrical housing having a vertical axis,which is closed at each end by a convex plate and in which a horizontalplate supporting a plurality of vertical cartridges or candles isdisposed. These cartridges or candles are constituted by, for example,perforated hollow cylinders about which may be wound a sleeve ofsynthetic fiber which may receive a layer of material known as apreliminary layer for example ion exchange resin, diatomaceous earth,cellulose or active carbon, selected in terms of the water to befiltered. The water to be filtered is introduced at the base of thefilter, penetrates inside the cartridges or candles and the treatedwater is collected by piping in the upper portion of the filter.Moreover, a vent is provided on the upper convex plate and provides anair drain.

These filters are used in the nuclear industry to treat radioactivewater and are therefore disposed in a protective housing, generally ofconcrete, handling and dismounting of these filters being carried out ata distance through an orifice drilled in the protective housing. As theoutlet piping for the air and the water in the upper part of the filtercomplicate such operations, access to the connection flanges isdifficult.

In some filters the vertical filter elements are supported by afloor-plate disposed at the base of the filter above a water collectionchamber for the treated water which is discharged at the lower portionof the filter. An air drain is, however, necessary in the upper portionof the filter. In addition, the dismounting of the filter elementsrequires the removal through the top, of the assembly in the housingabove the floor-plate supporting the filter elements, which represents aconsiderable weight.

It is an object of this invention to provide a filter in an improvedform.

SUMMARY OF THE INVENTION

According to the invention there is provided a filter comprising avertically disposed housing, a support plate, vertical filter elementsfixed at their upper ends to the support plate and supported thereby inthe housing, a water outlet pipe passing through the center of thesupport plate and exiting at the base of the filter, means forconnecting the support plate to the water outlet pipe in leak-tightmanner, and means whereby the portion of the filter located above thesupport plate can be removed.

The support plate may be connected in a leak-tight manner to the wateroutlet piping by means of two flanges, one of which is fixed to thepiping and the other to one end of a tie member, for example a bellows,fixed at its other end to the plate, an O ring interposed between theflanges, and locking clamps disposed within the piping and provided tourge the two flanges together.

The bellows support displacements due to the pressurization of thefilter and/or pressure loss increases in the filter elements. The platemay be released by a simple operation, possibly from a distance, of theclamps which rock inside the piping. The plate may then be readilylifted with the filter elements and the compensation bellows.Re-positioning of the plate is carried out using the same method in thereverse order.

In a particular embodiment of the invention, the support plate and theupper portion of the filter carry castors disposed in at least twodifferent planes and movable in guide rails fixed to a protectivehousing positioned around the filter. These castors and rails facilitatethe displacement of the plate and the upper portion of the filter. Inaddition, they prevent any large-scale lateral movements during mountingof the plate and the upper portion of the filter as well as any risk ofdamage to the water outlet piping.

The guide rails may be adjusted in height by means of threaded rods andnuts, which enables the play between the rails and the castors to beadjusted. They are advantageously funnel-shaped in their upper portionand this facilitates the positioning of the plate and the upper portionof the filter, as these elements are automatically centered during theirdescent between the guide rails. Centering elements may be provided onthe support plate and on the upper portion of the filter, which enablesperfect positioning of the elements.

Preferably, a pipe forming an air passage is disposed in the wateroutlet pipe, and exits at its upper end near the upper end of the filterand at its lower end at the base of the filter.

DESCRIPTION OF THE DRAWINGS

The invention will now be more particularly described, by way ofexample, with reference to the accompanying drawings, wherein:

FIG. 1 is an axial section through one embodiment of a filter accordingto the invention, and

FIG. 2 shows a detail of the filter of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, the filter shown therein comprises acylindrical housing 1 having a vertical axis. The housing 1 is definedby a lower sleeve 2 and an upper sleeve 3, the volume of the sleeve 3representing between one-fifth and one-third of the volume of thefilter. The filter is closed by two convex plates 4 and 5. The twosleeves are fixed to one another by external locking clamps 6, with theinterposition of a support plate 7. An inlet pipe 8 for water to betreated communicates with the lower portion of the filter. Verticalfilter elements 9 are fixed to the support plate 7 by their upper ends,and extend downwardly into the lower portion of the filter.

A vertical pipe 10 for the outlet of the treated water passes throughthe center of the support plate 7. The pipe is fixed to the plate asdescribed below and it emerges from the base of the filter as shown at11. A pipe 12 disposed inside the pipe 10 and connecting the upperportion of the filter, in the vicinity of the plate 4, to a lower drain13, forms an air drain.

The support plate 7 and the pipe 10 are fixed to one another in aleak-tight manner as shown in FIG. 2.

An O ring 14 is held between two flanges--a first lower flange 15 and asecond upper flange 16. The flange 15 is welded to the water outlet pipe10, and the flange 16 is welded to one of the ends of a metallic bellows17 whose other end is welded to the plate 7 which supports the filterelements. The flanges 15 and 16 are clamped together by clamps 18carried by supports 19 disposed inside the pipe 10.

The sleeve 3 and the edge of the support plate 7 have mounts 20 fixedthereto for movable castors 21 which are disposed in guide rails 22distributed around the filter and fixed to a protective housing 23 inwhich the filter is disposed. The upper end 22a of the rails 22 isfunnel-shaped. The filter which is described above may be readilydismounted, even by remote control. After the filter has been completelyemptied, the sleeve 3 is unfastened from the sleeve 2 by unclamping ofthe clamps 6, then completely removed to enable access to the plate 7which supports the filter elements 9. No pipes complicate thisoperation. The removal of the support plate 7 is carried out in twostages; the clamps 18 which ensure leak-tightness on the filtered wateroutlet pipe 10 are firstly unscrewed and swung inside this pipe; theplate 7 and the filter elements are then raised without difficulty.Mounting takes place in the reverse order and is facilitated by theguide rail assembly.

In a particular example a filter, 4.00 m in total height and 1.80 m inexternal diameter, is arranged with a plate supporting 570 candles ofpreliminary layer and disposed 0.865 m from the top of the filter. Thesupport plate is connected to the water outlet pipe by leak-tightdevices comprising six locking clamps. Four guide rails are fixed to theconcrete housing protecting the filter. The assembly and re-assembly ofthe filter and the filter elements may be readily carried out by remotehandling.

We claim:
 1. A filter comprising a vertically disposed filter housing, asupport plate, vertical filter elements fixed at their upper ends to thesupport plate and supported thereby in the housing, a water inlet in thelower portion of the filter, a water outlet pipe passing through thesupport plate and exiting at the base of the filter, two flangesconnecting the support plate to the water outlet pipe in leak-tightmanner, one of said flanges being fixed to the pipe and the other flangebeing fixed to one end of a bellows fixed at its other end to the plate,on O ring interposed between the flanges, and locking clamps disposedinside the pipe and provided to urge the two flanges together, aprotective housing positioned around the filter housing, guide railsfixed to the protective housing, and castors carried by the supportplate and the upper portion of the filter and being disposed in at leasttwo different planes and movable in the guide rails.
 2. A filter asclaimed in claim 1, wherein the guide rails are funnel-shaped at theirupper ends.
 3. A filter as claimed in claim 1, wherein a pipe forming anair passage is disposed in the water outlet pipe and exits at its upperend near to the upper end of the filter and at its lower end at the baseof the filter.
 4. A filter as claimed in claim 1, wherein the plate isdisposed so that the volume of the portion of the filter located abovethe plate represents between one-fifth and one-third of the total volumeof the filter.